Table 3.
Comparative performance of AFB Smear, Culture and two in house PCR dot-blot methods stratifying by HIV status
| Laboratory Results and Performance of methods |
HIV seronegative Groupa N = 203 |
HIV seropositive Groupb N = 74 |
|||||||
|---|---|---|---|---|---|---|---|---|---|
| TB N = 88 |
Non-TB N = 115 |
TB N = 40 |
Non-TB N = 34 |
||||||
| Performance of AFB smear |
Positive | 60 | 1 | 17 | 0 | ||||
| Negative | 28 | 114 | 23 | 34 | |||||
| SE (%) |
SP (%) |
PPV (%) |
NPV (%) |
SE (%) |
SP (%) |
PPV (%) |
NPV (%) |
||
| 68 | 99 | 98 | 81 | 43 | 100 | 100 | 60 | ||
| CI 95(%) | 57,9-77,2 | 95,8-99,9 | 92,2-99,9 | 73,2-86,2 | 28,0-58,0 | 91,6-100 | 83,8-100 | 46,6-71,7 | |
| Performance of Culture |
Positive | 75 | 0 | 32 | 0 | ||||
| Negative | 13 | 115 | 8 | 34 | |||||
| SE (%) |
SP (%) |
PPV (%) |
NPV (%) |
SE (%) |
SP (%) |
PPV (%) |
NPV (%) |
||
| 85 | 100 | 100 | 90 | 80 | 100 | 100 | 81 | ||
| CI 95(%) | 76,3-91,5 | 97,4-100 | 96,1-100 | 83,7-94,2 | 65,5-90,3 | 91,6-100 | 91,0-100 | 67,0-90,7 | |
| Performance of PCR dot-blot |
Positive | 66 | 17 | 29 | 5 | ||||
| Negative | 22 | 98 | 11 | 29 | |||||
| SE (%) |
SP (%) |
PPV (%) |
NPV (%) |
SE (%) |
SP (%) |
PPV (%) |
NPV (%) |
||
| 75 | 85 | 79 | 82 | 72 | 85 | 85 | 72 | ||
| CI 95(%) | 65,2-83,2 | 77,1-90,9 | 69,8-87,2 | 74,0-87,8 | 57,2-84,6 | 70,4-94,4 | 70,4-94,4 | 57,2-84,6 | |
| Performance of PCR-AG |
Positive | 38 | 27 | 17 | 8 | ||||
| Negative | 50 | 88 | 23 | 26 | |||||
| SE (%) |
SP (%) |
PPV (%) |
NPV (%) |
SE (%) |
SP (%) |
PPV (%) |
NPV (%) |
||
| 43 | 76 | 58 | 64 | 42 | 76 | 68 | 53 | ||
| CI 95(%) | 33,1-53,7 | 68,1-83,6 | 46,2-69,9 | 55,5-71,5 | 28,0-58,1 | 60,2-88,4 | 48,1-83,8 | 39,1-66,6 | |
SE: Sensitivity, SP:Specificity, PPV: Positive Predictive Value, NPV: Negative Predictive Value
aHIV seronegative Group
bHIV seropositive Group